1. Field of the Invention
This invention relates in general to gas furnaces and, in particular, to the cell panel positioned between the burner box and heat exchanger cells of a gas furnace. More specifically, but without restriction to the particular embodiment hereinafter shown and described, this invention relates to burner target plates formed in the cell panel by extrusion.
2. Discussion of the Prior Art
Gas furnaces typically include a primary heat exchanger positioned adjacent a burner box containing burners. During operation of the furnace, a blower moves circulating air over the heat exchanger to produce heated air that is directed to a desired location. Gas is supplied to the burner box by a gas manifold having orifices that direct the gas into the burners. The gas exiting the burners is ignited by an ignitor provided in the burner box. The burners allow combustion of the gas as well as direct heat into the heat exchanger. The typical heat exchanger includes cells with a channel or pass formed in each cell to direct the flow of heat and flue gas produced by combustion. These cells are positioned side by side in a parallel manner and are provided with a predetermined spacing to allow the blower air to flow around the cells. The blower air is thus heated by convection as it moves over the cells.
Each of the channels in the primary heat exchanger cells includes a flared inlet port as well as a discharge port. A sheet metal panel or cell panel having burner target plates is typically provided to position the burner box relative to the cells contained in the heat exchanger. The burner target plates provided in the cell panel serve two functions in that they provide a seat for the flared inlet port of a corresponding heat exchanger panel while also providing a zone or target area with a central opening at which a corresponding burner is directed so that heat and flue gas produced by combustion is directed into the corresponding heat exchanger cell.
Prior art burner target plates are individually manufactured in a separate stamping process and then either fastened to large stamped openings provided in the cell panel or similarly fastened to a smaller sheet metal panel secured to the discharge side of the burner box. In the former arrangement, the burner box has an un-paneled discharged side which is secured to the cell panel to cover the area containing the target plates.
The residential heating industry has advanced with the advent of condensing gas furnaces. These furnaces typically included a primary heat exchanger as well as a condensing heat exchanger. A blower in these condensing heat furnaces similarly provides circulating air flow over both heat exchangers to produce heated air that may be directed to a desired location by a system of ductwork and registers.
In such condensing furnaces, both the primary heat exchanger and the condensing heat exchanger include cells with a channel or pass formed therein to direct the flow of flue gas produced by combustion. These cells in both the primary and secondary heat exchangers are positioned side by side in a parallel manner and are provided with a predetermined spacing to allow blower air to flow around both groups of heat exchanger cells. Gas is similarly provided to the condensing furnace by a gas manifold having orifices that direct the gas into burners contained in a burner box. The gas is ignited by an ignitor as it exits the burners contained in the burner box. The heat and flue gas produced by combustion is then directed into the primary heat exchanger cells and induced to move through the heat exchangers.
Each of the channels provided in the primary heat exchanger cells eventually terminates at a discharge port. The discharge ports of the primary heat exchanger are typically aligned and secured in a first sheet metal panel forming the discharge side of the primary heat exchanger.
The condensing heat exchanger of the furnace is configured in a similar manner to its primary heat exchanger. A series of side by side condensing cells is provided. Each of these condensing cells has an inlet port for receiving flue gas discharged from the primary heat exchanger. The inlet ports of the condensing heat exchanger cells are aligned and secured in a second sheet metal panel forming the inlet side of the condensing heat exchanger. The two heat exchangers are mounted together to form a single intrical unit capable of receiving and heating clean circulating air provided from the blower. These condensing gas furnaces similarly include a cell panel including burner target plates for aligning the primary heat exchanger cell and directing burner discharge into the cells.
Although the condensing gas furnace is an advancement over prior gas-fired furnaces including only a primary heat exchanger, the cell panels typically used in these condensing gas furnaces are similar to those used in the prior single heat exchanger furnaces. The cell panels in current condensing gas furnaces also require the manufacturing of individual burner target plates that are fastened to large openings provided in the burner box area of the cell panel or similarly fastened to openings provided on the discharge side of the burner box which would then be mounted to an appropriate opening in the cell panel.